For my friend who is a professional mechanic
and owns his first vanagon-90 manual trans

he has done 4 or 5 engine transplants for
all the Vanagon folks around here-- never a problem..

Engine cranks fine but won't start-

spark weak

Have changed
1. fuel pump (getting fuel)
2. distributors-(new Bosch cap and rotor)
3. computer
4. AFM

Battery A-OK
quality of fuel OK
plug wires New as are plugs cap and rotor
getting voltage to coil

Van was running well-over a week or two-- gradual
bucking-chugging at low speeds and above 10 MPH behaved normally--
grounds have been cleaned and jumped-

What now??

thx
Steve